1951 Jrnl. Brit. Interplanetary Soc. 10 42 A criterion for the proper design of liquid rocket motors to ensure freedom from the phenomenon of ‘chugging’ without unnecessary increase in fuel-tank or fuel-pump pressures.

1952 Jrnl. Brit. Interplanetary Soc. 11 52 An hypothesis that low-frequency oscillations (chugging) sometimes observed in liquid propellant rocket engines, are the result of oscillatory propellant flow induced by a combustion time lag.

1964 Engineering 14 Feb. 270/2 A surging effect sometimes occurs in rocket engines and is called ‘chugging’.

2003 Guardian 9 July b10/1 Some find the enthusiastic fundraisers annoying, or see them as little better than well-meaning muggers (‘chugging’ being one tag for what they do).

2006 K. O'Halloran Charity Law & Social Inclusion x. 268 The provisions fail to deal with Internet, email or text messaging appeals and only some deal with ‘face to face chugging’.

2012 Evening Standard 22 Aug. 20 The practice of ‘chugging’ has come under fire after a Sunday Telegraph expose showed that street fundraisers were breaking the code of conduct.